three groups:>60,39-60,<39MPa.It is noted that the composition dependen- ce of strength is generally consistent with that in the case of strain rate of 10-2/s,but the alloy having NbTiAls composition is the best. A000 800 600 Fig.11 Strength-temperature dependence for the Nb-Ti-Al system 400% 1、1+92、11+a1,3、11,4、y1,5、1, 200 6、7 R.T.600 800 1n0 T/℃ Fig.12 Typical fractography a.at room temperature b.at 1100C. In the compressive test the final reduction was controlled to be 45%,with the radial real strain being approximatcly 80%.No crack was observed on the sample surface for most the alloys studied,indicating good high temperature formability.The temperature dependenc of o.2 at strain rate of 10-2/s for part of the alloys are shown in Fig.11.The result indicates that for the alloy in the phase range of y1,n,y,y+n and yi+az an abnormal tempe- rature-strength dependence existes,No data of elongation at room leperature has been obtained.From the fractography it is clearly scen that the dominant fracture mode in the tensile condition for all the alloys investigated is essenti- ally brittle cleavage.However,the fraction of intergranular fracture for 1100C test increases as the high temperature strength of alloys increases (Fig.12). 3 Conelusion The evaluation for NB-Ti-Al ternary intermetallic alloys has shown their 166， 一 ， 一 ， 」 只 口 厂 一一厂一一厂一一飞尸不一 一 ’ 吕 口 一 一 一 ， 钧 ， 夺 钧 场比，一。口闪 、 飞 刀 ， 、 · 一 卜 ， 、 飞 ， ， 、 、 刃 ‘ 乙 吕口口 犷 汇 日约口 丁 ℃ 。 ， 二 ， 士 『。 一 。 。 夕 ， 刀， 夕哎 ， 夕、 刀 夕 一 ， 。 。 工 ， 一 。 ” 一 一 八 “ 犷 犷 耳 主 孚